import java.util.LinkedList;
import java.util.Queue;
import java.util.Scanner;



// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static int i;
    static class TreeNode{
        public char val;
        public TreeNode left;
        public TreeNode right;
        public TreeNode(char val){
            this.val = val;
        }
    }
    public static TreeNode creatTree(String s){
        if(s.charAt(i) != '#'){
            TreeNode root = new TreeNode(s.charAt(i));
            i++;
            root.left = creatTree(s);
            root.right = creatTree(s);
            return root;
        }else{
            i++;
            return null;
        }
    }


    public static void main(String[] args) {
        System.out.println("_______________________");
        Queue<Integer> queue = new LinkedList<>();
        queue.add( );
        queue.add( );
        queue.add( );
        queue.add( );
        queue.add( );
        int a  = queue.poll();
        queue.remove();
        System.out.println(queue.toString()+a);
    }
    public static void middleOrder(TreeNode root){
        if(root == null){
            return;
        }else{
            middleOrder(root.left);
            System.out.print(root.val+" ");
            middleOrder(root.right);
            
        }
    }
}
